Diagnosis
This is an error sequence. The base does not detect the container, or the container is not locked into place correctly.
How to Fix It
Lift the container straight off the base. Align the arrow on the container with the arrow on the base. Press down firmly until you hear and feel a distinct click. The container should not wobble.
If That Didn't Work
The problem could be in the container's drive coupling. Look at the black plastic square drive on the bottom. If it's cracked, chipped, or excessively worn, it won't engage the sensor. You need a new container.
Heads Up
The flashing light is a safety feature. Do not try to bypass it or run the motor without a properly engaged container. You can damage the drive system.